Muscles Of The Back

Question 1

Trapezius

Answer 1

Superficial group
Origin: superior nuchal line, external occipital protuberance, ligamentum nuchae, spinous processes of C7 to T12
Insertion: lateral one third clavicle, acromion, spine of scapula
Innervation: motor-accessory nerve CNXI, proprioception- C3 and C4
Function: assists in rotating the scapula during abduction of humerus above horizontal; upper fibres elevate, middle fibres adduct and lower fibres depress scapula

Question 2

Latissimus dorsi

Answer 2

Superficial group
Origin: spinous processes of T7 to L5 and sacrum, iliac crest, ribs 10 to 12
Insertion: floor of intertubercular sulcus of humerus
Innervation: thoracodorsal nerve C6-C8
Function: extends, adducts and medially rotates humerus

Question 3

Levator scapulae

Answer 3

Superficial group
Origin: transverse processes of C1 to C4
Insertion: upper portion medial border of scapula
Innervation: C3 to C4 and dorsal scapular nerve (C4 C5)
Function: elevates the scapula

Question 4

Rhomboid major

Answer 4

Superficial group
Origin: spinous processes of T2 to T5
Insertion: medial border of scapula between spine and inferior angle
Innervation; dorsal scapular nerve C4 C5
Function: retracts (adducts) and elevates scapula

Question 5

Rhomboid minor

Answer 5

Superficial group
Origin: lower portion of ligamentum nuchae, spinous processes of C7 and T1
Insertion: medial border of scapula at spine of scapula
Innervation: dorsal scapular nerve C4 C5
Function: retracts (adducts) and elevates the scapula

Question 6

Serratus posterior superior

Answer 6

Intermediate group
Origin: lower portion of ligamentum nuchae, spinous processes of C7 to T3 and supraspinous ligaments
Insertion: upper border of ribs 2 to 5 just lateral to their angles
Innervation: anterior rami of upper thoracic nerves T2-5
Function: elevates ribs 2 to 5

Question 7

Serratus posterior inferior

Answer 7

Intermediate group
Origin: spinous processes of T11 to L3 and supraspinous ligaments
Insertion: lower border of ribs 9 to 12 just lateral to their angles
Innervation: anterior rami of lower thoracic nerves T9-T12
Function: depress ribs 9 to 12 and may prevent lower ribs from being elevated when diaphragm contacts

Question 8

Splenius capitis

Answer 8

Deep group spinotransversales muscle
Origin: lower half of ligamentum nuchae, spinous processes of C7 to T4
Insertion: mastoid process, skull below lateral one third of superior nuchal line
Innervation: posterior rami of middle cervical nerves
Function: together- draw head backward, extending neck, individually- draw and rotate head to one side turn face to same side

Question 9

Splenius cervicis

Answer 9

Deep group, spinotransversales muscle
Origin: spinous processes of T3 to T6
Insertion: transverse processes of C1 to C3
Innervation: posterior rami of lower cervical nerves
Function: together-extend neck, individually- draw and rotate head to one side turn face to same side

Question 10

Extrinsic back muscles

Answer 10

Involved in upper limb movement and respiration
Generally innervated by ventral rami
Lie superficial to intrinsic muscles
Layer 1- most superficial layer runs between upper limb and axial skeleton consists of trapezius and Latissimus Dorsi
Layer 2- levator scapulae and rhomboid muscles
Layer 3- Serratus posterior superior and inferior which have an assisting role in respiration

Question 11

Intrinsic back muscles

Answer 11

Involved in movement and maintaining posture
Enclosed in deep fascia- in neck region (ligamentum nuchae) in thoracolumbar region (thoracolumbar fascia)
Generally innervated by dorsal rami
Deepest layer generally innervated by dorsal rami, layer 5 has mixed innervation from both dorsal and ventral rami
Layer 4- spinotransverse (splenii) muscles and erector spinae (spinalis, longissmus and iliocostalis)
Layer 5- transversospinale group (semispinalis, multifidi and rotares)
Layer 6- suboccipital muscles in cervical region, short muscles along spine

Question 12

Splenii muscles spinotransverse

Answer 12

Are in neck region and extend and rotate the head

Question 13

Erector spinae

Answer 13

Run along the whole spine and insert into a combined tendinous origin into the lumbosacrum
Generally flex, extend and laterally flex the spine
From medial to lateral: spinalis, longissmus, iliocostalis

Question 14

Transversospinale group

Answer 14

Semispinalis , multifidi and rotares

Question 15

Suboccipital muscles

Answer 15

Cervical region
Rectus capitis major, rectus capitis minor, oblique capitis superior, oblique capitis inferior

Question 16

Short muscles

Answer 16

Along spine
Interspinalis
Intertransversarii
Attaching inbetween the spinous process and transverse processes respectively

Question 17

What movements are attainable at the spine

Answer 17

Flexion
Extension
Lateral flexion
Rotation